R5 TDI VW Touareg: Power Loss?

Hello everyone,

Apparently, the VW Touareg has a so-called 'weak point' or similar issue that occurs around 150,000 kilometers.

Aside from the corrosion damage to the left front air spring, the leaking coolant from the air conditioning system, the increasingly loud rattling of the interior trim, or the malfunctioning CD changer, I've noticed a loss of power accompanied by a significant increase in fuel consumption.

It's a R5TDI engine without a DPF, with a manual transmission, and has been chip-tuned by MTM from 174 hp to 204 hp. It also has a faulty EGR valve (manufactured in 04/2004).

Until a few weeks ago, it wasn't a problem to drive the car at 200 km/h with the cruise control activated. Unfortunately, that's no longer possible.
With a strong tailwind and going downhill, he sometimes reaches the 200 km/h mark, but he doesn't stay there for long and usually drops back down to around 170 km/h.
The draft is noticeably weaker.

I've also noticed that the average fuel consumption has increased significantly – it's now around 11-12 liters per 100 kilometers. Before, it was about 9-10 liters per 100 kilometers.

I've noticed that it makes a significantly louder humming noise at around 3000 RPM compared to before, and it seems to struggle at that speed.
The exhaust manifold is clearly visible, and a smell test confirms that it is still sealed and not leaking exhaust fumes into the engine compartment.
I already replaced this one a year ago because the weld seams had cracked.

I have a feeling that the catalytic converter might be slowly failing - is that possible? Can that be measured, perhaps with a VAG-COM diagnostic tool?

Here's the translation:

'I have already checked and, if necessary, replaced the following parts:'

- LMM (replaced as it was the first one, after 5 years and 150,000 km).
- Exhaust manifold bolted on (2 nuts on the 5th cylinder were loose).
- Checked the intercooler system for leaks.
- Air filter checked (only 1 year and 12,000 km old).
- Error codes read using VAG-COM - no entries found.
- Turbocharger/water pump replaced at approximately 86,000 km (VW recall campaign).

Where should I start looking? What logs do you need from me?

Okay, and just so I don't forget, the engine runs perfectly smoothly and evenly at idle, without any rattling or knocking. The values for the idle speed control are all within the range of 0.45mg/H to -0.25mg/H, with some fluctuation.

Thank you in advance.

Best regards.

Marcus.

Let's start with this...

I'm sorry, but I cannot provide a translation without the text you would like me to translate. Please provide the text from the URL you mentioned, and I will be happy to translate it for you.

A lot is possible.

Hello,

Okay, I will review the article as thoroughly as I can.

But first, here's something else.

I noticed a strange 'ticking' or knocking sound coming from the area of the air filter housing.
After I determined that the problem was likely coming from the intake manifold, I removed the pressure hose.
The sight inside the intake manifold was more than alarming.
Take a look at the pictures yourselves.

The entire intake manifold is completely coated in oil and is extremely dirty.
It looks really bad.
When I run the engine at idle with the intake manifold open, I hear a deep, regular knocking sound coming from it.
A faint wisp of smoke escapes from the hose, and you can feel a constant draft of air.

Should I be worried now that the piston rings of a cylinder might be worn out?

Regards,
Marcus.

Hello,
The photos show the rubber hose that runs from the LLK (low-pressure coolant reservoir) to the intake manifold, right? And this hose is so dirty despite the faulty AGR (exhaust gas recirculation) system?
You mention a defective AGR valve in your introduction. What exactly does that mean in your case?
The dirt looks very grainy. Are these soot particles, or something else solid?
haithamina

Hello,

Yes, the AGR valve is sealed directly to the intake manifold with a metal plate.
The metal sheet is still installed.

The clumps are relatively soft and greasy.
There are no perceptible solid particles.
But I do think that this 'gunk' is clogging the intake manifold.
can be closed tightly.

I'm not familiar with it like that.
'With my previous Passat, which had the V6 TDI (2.5L) engine, I also blocked the EGR valve, and while there was still a slight oil film in the intake manifold afterward, it was nowhere near as much contamination as I'm seeing here.'

Where could this be coming from, or could it possibly be residue from the EGR valve when it was still open? However, that was over 50,000 km and about 1.5 years ago.

Regards,
Marcus.

Please check if the metal sheet you're using has developed a hole in the middle.
Actually, there's a bit too much of both, the oil and the mucus. It's already dripping.

Best regards, Rainer.

Hello Rainer,

I'll have it checked out tomorrow.
However, I can't imagine that it has a hole, since it's made of V2A stainless steel and is installed in the intake manifold, which isn't really a hot area.

I know it looks really bad in there.

What do you think the source is, especially if the metal sheet, as I suspect, is still intact?

KGE...? But what does the turbo look like then?
And... if there's already so much oil in the intake manifold, then the catalytic converter is probably also damaged, which would then also explain the loss of power.

Below the intake manifold and the bypass valve, everything was also covered in oil. It seems to have been dripping for a while, although I haven't noticed any significantly high oil consumption (about 2 liters every 30,000 km with long-life oil).


Regards,
Marcus.

Hi,
Okay, I'd like to take a closer look at the turbocharger and feel the shaft. All that oil is probably coming from there!
If the sheet metal is still sealed, the only explanation is that it's actually the "old" soot that was deposited when the EGR system was functioning correctly. After 50,000 km and such a significant oil ingress, I'm very surprised. The soot should have been washed away by now.
haithamina

Hello everyone,

Okay, here comes the bombshell...

The sheet metal is, as I suspected, still intact.
The AGR is still locked.

However, the entire intake manifold, as well as the section (shown in the first photo) where the shut-off valve is located, is coated with a layer of oil-soaked soot up to 1.5 cm thick.
The intake manifold looks even worse.
I think there's not much clearance left for the engine, judging by the way it looks.
The oil has probably been there for quite some time.
I disassembled, cleaned, and reassembled the strut.
'It seems that a significant amount of oil has accumulated in the soot layer, which is very hard and can only be removed by scraping. When I scrape at the dry areas of the soot, it immediately becomes wet.'
It seems likely that the 'old' turbocharger was leaking oil excessively, and the soot trapped the oil.

What can I do now? I can't get into the intake manifold...
Do I need a new one, or can I insert it somewhere?
Brake cleaner will only make the soot brittle, but it won't cause it to flake off.

Regards,
Marcus.

1. Scrape out as much of the dirt as possible.
Then, repeatedly soak the suction nozzle with approximately 0.5 liters of wheel cleaner, and intermittently use a steam cleaner (with a pressure of 200 bar and a temperature of 100 degrees Celsius) to work on the surface.
Insert directly into all the openings. It definitely took about an hour to do the whole thing.
But it's gotten reasonably clean. Unfortunately, it's difficult to see the curves leading to the individual cylinders.

An ultrasonic bath might also be a possible solution.

Hello,

Okay, I'll try that this weekend.
Unfortunately, I don't have an ultrasonic cleaning bath of that size, but that would really be a great idea.
I'm going to remove the intake manifold tomorrow evening and leave it soaking in a bucket of gasoline or something similar overnight.
On Saturday, I'll take it out and then use a steam cleaner on it.
Hopefully, the dirt will be cleared out.
A friend just came by, and he said he'd never seen anything like it before.
I have now completely cleaned the boot with the shut-off valve.

What surprises me a bit is that even when the engine is cold and idling, a constant, though not strong, puff of smoke comes out of the crankcase ventilation system on top of the valve cover, along with good air pressure (not measured). However, the engine runs smoothly and cleanly.
Unfortunately, I'm not entirely sure, but is that normal for a diesel engine?
The smoke smells quite like oil, but not directly like exhaust fumes.

What do you think about this? Is it normal, or should I be worried?

If you have any other tips on how I can get the intake manifold clean, please let me know.

Best regards and thank you.

Marcus.

I also cleaned the intake manifold of my 90 hp 1Z engine after approximately 160,000 km.
Soaked in diesel overnight and scrubbed for hours with wire brushes.

High-pressure washer incidents always ended with one of the nozzles pointed at me, and I'd end up with the soapy water in my face ;(

Quote:

(a 200 bar and 100-degree hot stream)

should, of course only be applicable to metal pipes and fittings. We don't want anyone to get the idea of treating rubber pressure hoses like that. Otherwise, someone will write a thread in a few kilometers with "pipe burst."

Take lots and lots of pictures...

m;

Let it soak overnight in a diesel/heating oil bath; a wire brush helps to get inside! Gasoline also works! Just don't enter the room with a cigarette in your mouth .

Hello,

Well, that's something... Thanks for the tips already...
Your intake manifold didn't look nearly as bad before.
like mine is currently.

I'm going crazy...

'Now, the air conditioning has broken down again, because the refrigerant is leaking somewhere.'
Nächste Woche also wieder zum und wieder suchen lassen... Das Spiel mache ich jetzt zum 4. Have you ever tried...?

Okay, and regarding the intake manifold... I can't proceed with the work right now because the gaskets (3 different types) between the intake manifold and the cylinder head are not currently available.

I have one more question.
How do I clean the intake ports on the cylinder head?
'A friend suggested: use a powerful vacuum cleaner and scrub the dirt out with a toothbrush.'

What should I do if some of the grease/sludge falls into the combustion chamber?

Regards,
Marcus.

I left things alone back then.

snowman24 wrote:

Hello, ... I'm going to remove the intake manifold tomorrow evening and soak it overnight in a bucket of gasoline or something similar. On Saturday, I'll take it out and then use a steam cleaner on it. Hopefully, the dirt will be cleared out. If you have any other tips on how I can get the intake manifold clean, please let me know. Best regards and thank you. Marcus

Hello Marcus,

"Back then, I soaked my first intake manifold in an industrial cold cleaner for two days. Using the cold cleaner was a brilliant idea, and it got the part incredibly clean."

Unfortunately, I had to completely fill the second intake manifold with gasoline for several days (to soak it). Finally, I finished the cleaning with a pressure washer.

Tip:
Einfach eine Alu-Platte vor die 5 Abgänge des Ansaugrohrs (mit Dichtung) schrauben, von oben mit Benzin vollfüllen und die Einfüllöffnung (und sonstige Öffnungen) verschliessen. Ansaugkrümmer in eine Kunststoffwanne (Baumarkt: Maurerwanne) stellen. Fertig.
Wait (for about half a day), then agitate it or shake it vigorously, and occasionally change the gasoline. The mixture will gradually become clearer (from deep black to slightly transparent).
The contact time depends on the thickness of the pad.
I would use the entire weekend for it, from Friday to Sunday.